3 files changed, 50 insertions, 10 deletions
diff --git a/src/test/fuzz/integer.cpp b/src/test/fuzz/integer.cpp
index d5b5ec3c9a..35d6804d4f 100644
--- a/src/test/fuzz/integer.cpp
+++ b/src/test/fuzz/integer.cpp
@@ -148,11 +148,7 @@ void test_one_input(const std::vector<uint8_t>& buffer)
 
     const CScriptNum script_num{i64};
     (void)script_num.getint();
-    // Avoid negation failure:
-    // script/script.h:332:35: runtime error: negation of -9223372036854775808 cannot be represented in type 'int64_t' (aka 'long'); cast to an unsigned type to negate this value to itself
-    if (script_num != CScriptNum{std::numeric_limits<int64_t>::min()}) {
-        (void)script_num.getvch();
-    }
+    (void)script_num.getvch();
 
     const arith_uint256 au256 = UintToArith256(u256);
     assert(ArithToUint256(au256) == u256);
diff --git a/src/test/fuzz/message.cpp b/src/test/fuzz/message.cpp
new file mode 100644
index 0000000000..dfa98a812b
--- /dev/null
+++ b/src/test/fuzz/message.cpp
@@ -0,0 +1,48 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <chainparams.h>
+#include <key_io.h>
+#include <optional.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+#include <util/message.h>
+#include <util/strencodings.h>
+
+#include <cassert>
+#include <cstdint>
+#include <iostream>
+#include <string>
+#include <vector>
+
+void initialize()
+{
+    static const ECCVerifyHandle ecc_verify_handle;
+    ECC_Start();
+    SelectParams(CBaseChainParams::REGTEST);
+}
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    const std::string random_message = fuzzed_data_provider.ConsumeRandomLengthString(1024);
+    {
+        const std::vector<uint8_t> random_bytes = ConsumeRandomLengthByteVector(fuzzed_data_provider);
+        CKey private_key;
+        private_key.Set(random_bytes.begin(), random_bytes.end(), fuzzed_data_provider.ConsumeBool());
+        std::string signature;
+        const bool message_signed = MessageSign(private_key, random_message, signature);
+        if (private_key.IsValid()) {
+            assert(message_signed);
+            const MessageVerificationResult verification_result = MessageVerify(EncodeDestination(PKHash(private_key.GetPubKey().GetID())), signature, random_message);
+            assert(verification_result == MessageVerificationResult::OK);
+        }
+    }
+    {
+        (void)MessageHash(random_message);
+        (void)MessageVerify(fuzzed_data_provider.ConsumeRandomLengthString(1024), fuzzed_data_provider.ConsumeRandomLengthString(1024), random_message);
+        (void)SigningResultString(fuzzed_data_provider.PickValueInArray({SigningResult::OK, SigningResult::PRIVATE_KEY_NOT_AVAILABLE, SigningResult::SIGNING_FAILED}));
+    }
+}
diff --git a/src/test/fuzz/scriptnum_ops.cpp b/src/test/fuzz/scriptnum_ops.cpp
index 42b1432f13..f4e079fb89 100644
--- a/src/test/fuzz/scriptnum_ops.cpp
+++ b/src/test/fuzz/scriptnum_ops.cpp
@@ -129,10 +129,6 @@ void test_one_input(const std::vector<uint8_t>& buffer)
             break;
         }
         (void)script_num.getint();
-        // Avoid negation failure:
-        // script/script.h:332:35: runtime error: negation of -9223372036854775808 cannot be represented in type 'int64_t' (aka 'long'); cast to an unsigned type to negate this value to itself
-        if (script_num != CScriptNum{std::numeric_limits<int64_t>::min()}) {
-            (void)script_num.getvch();
-        }
+        (void)script_num.getvch();
     }
 }